Sucker fish prefer vegetable matter as treats, but also like sinking shrimp pellets. They also eat canned peas, canned green beans, cooked and cooled zucchini, raw zucchini and cooked and cooled peas. If the treats will not sink, they can be added to a small device called a produce clip.
I catch them all the time while trout fishing on small red worms.
So I would try them also here and there.